1. Field of the Invention
The present invention relates to a liquid electrophotographic printer, and more particularly, to an apparatus for recovering only the liquid carrier from a developer liquid in which toner particles are mixed with a liquid carrier by separating out moisture unavoidably fed during circulation of the developer liquid.
2. Description of the Related Art
A liquid electrophotographic printer such as a laser color printer includes a development unit 20 for supplying a developer liquid in which a toner powder is mixed with liquid carrier to a photoreceptor belt 10 as a photosensitive medium, and developing an image, a drying unit 30 for absorbing and evaporating the liquid carrier remaining after being adhered to and used in development of an electrostatic latent image formed on the photoreceptor belt 10, and a printing unit 40 for printing the image developed on the photoreceptor belt 10 onto a sheet of paper 1.
The drying unit 30 includes a drying roller 31 for drying the residual liquid carrier of the developer liquid supplied to the photoreceptor belt 10 to absorb the same, a heating roller 32 for heating the drying roller 31 to evaporate the absorbed liquid carrier, and a manifold 33 installed to enclose the drying roller 31 and the heating roller 32 so as to be blocked from the outside.
The liquid carrier absorbed into the drying roller 31 is evaporated by the heating roller 32 and then condensed by a condenser 50 to be stored in a purge tank 60 in a liquefied state.
The liquid carrier stored in the purge tank 60 is mixed with a concentrated ink supplied from an ink cartridge (not shown) in a predetermined mixture ratio and is supplied to the development unit 20 for being recycled as a developer liquid.
However, since it is difficult for the manifold 33 to enclose the drying roller 31 and the heating roller 32 to be completely blocked from the outside, air is inevitably induced from the outside.
Since the air induced from the outside contains moisture, the moisture is induced into the condenser 50 together with the gas carrier evaporated by the heating roller 32 to then be recovered and stored in the purge tank 60 in a condensed state into water droplets and liquid carrier.
Thus, if the liquid carrier recovered and stored in the purge tank 60 is mixed with a concentrated ink supplied from the ink cartridge to be used as the solvent of the toner particles, the developer liquid cannot be maintained in a desired concentration due to the induced water droplets, which makes development defective, lowering the print quality. In a liquid electrophotographic printer, it is an absolute requirement to separate moisture from the condensed and restored liquid carrier in order to attain a high quality print image.